Device for providing rapid communication between two reservoirs at different pressures



9, 1965 M. LECHEVALLIER 2 DEVICE FOR PROVIDING RAPID COMMUNICATION BETWEEN TWO RESERVQIRS AT DIFFERENT PRESSURES 2 Sheets-Sheet 1 Filed July 23, 1963 INVENTOR MA ale/cs A EC'HE VAL L w ATTORNEYS 9, 1965 M. LECHEVALLIER 3, ,61

DEVICE FOR PROVIDING RAPID COMMUNICATION BETWEEN TWO RESERVOIRS AT DIFFERENT PRESSURES 2 Sheets-Sheet 2 Filed July 25, 1965 INVENTOR Mame/cs ZECHE VA (.1. IE?

BY 35 mm ATTORNEY5 United States Patent Ofi ice 3,2166 1 l Patented Nov. 9, 1965 D 4 Claims. (c1. 220-89) The present invention relates to a device for providing rapid communication between two reservoirs at different pressures.

In safety devices between two enclosures at different pressures, it is known to provide an intermediate chamber arranged between the low pressure chamber and the high pressure chamber, with fluid-tight, destructible draphragms limiting the intermediate chamber on either side with respect to the two adjacent chambers. Such diaphragms are usually either of metal or plastics.

The pressure within the said intermediate chamber is made approximately equal to the mean of the pressure present in the two chambers. The .two diaphragms are therefore subject to equal differential pressures.

When the pressure in the intermediate chamber is reduced to the pressure in the low pressure chamber, the upper diaphragm, which is subject to a difference in pressure double that which it supports under initial conditions, is ruptured. The second diaphragm is destroyed in its turn, under the same conditions.

The two chief disadvantages of such devices are as follows:

First, the permanent stress undergone by the two diaphragms as a result of the pressure differences existing over their surfaces.

Second, the delay in the opening of the high pressure chamber, which is not as brief as might be desired, and which essentially depends on the speed of the rupture of the two diaphragms.

It is an object of the present invention to overcome these disadvantages, i.e., to avoid straining the two diaphragms in their initial state and also to achieve a shorter response time.

According to the invention there is provided a device which forms an intermediate chamber between the two reservoirs, and comprises a dished member fixed to a fluidtight diaphragm separating the intermediate chamber from the low pressure reservoir, the convex side of the dish facing the said intermediate chamber, and a striker member to shatter the said dish when the pressure in the intermediate chamber fal-ls below a predetermined value, said striker member being fixed on to a fluid-tight diaphragm separating the high pressure chamber from the intermediate chamber and facing the convex side of the dish.

In order that the invention may be more clearly understood, reference will now be made to the accompanying drawings which show one embodiment thereof, by way of example, and in which:

FIGURE 1 shows a sectional view of a device according to the invention mounted between two reservoirs,

FIGURE 2 shows a plan view of the dome employed in the embodiment of FIGURE 1, and

FIGURES 3a, 3b and 30 show three enlarged sectional views of the device according to the invention illustrating three successive stages in its operation.

By way of example, FIGURE 1 illustrates a device according to the invention used as a safety device in a nuclear reactor.

As is known, a reactor is stopped by sending a neutronabsorbing fluid such as borium fluoride into it. The safety obtained is a function of the rapidity with which the poison fluid is sent into the core of the reactor. The safety device may, for instance, be triggered by a metal pellet melting as soon as the reactor reaches a certain level of neutron flux or a temperature it is not to exceed. The reservoir in which the neutron-absorbing fluid is placed will hereinafter be called the storage chamber and the chamber in the core of the reactor receiving this fluid the release chamber." The assembly formed by the storage chamber and the release chamber is usually perfectly fluidtight so as to prevent the poison fluid from spreading through the reactor enclosure.

In FIGURE l, a fluid-tight safety enclosure 1 comprises a storage chamber 2 and a release chamber 3 between which a device to provide communication between the said two chambers is located.

Between chambers 2 and 3 is an intermediate chamber 4 which is constituted by the central portion of a cylindrical ring 5, the inner and outer diameters of which match the inner and outer diameters, respectively, of the storage chamber 2.

A second cylindrical ring 6, the inner and outer diameters of which match the inner and outer diameters, respectively, of the storage chamber 2, placed up against the cylindrical ring 5, holds the device in the assembled position.

The two cylindrical rings 5 and 6 are fixed to the storage chamber 2 by nuts and bolts such as 7 Within its mass, the cylindrical ring 5 is provided with an L-shaped channel 8 to allow the fluid kept in the intermediate chamber 4 to flow out. A tube 9 passing through the mass of the cylindrical ring 6 is located at the outer end 10 of the channel 8 in the cylindrical ring 5. This tube 9 is connected at its other end 11 to another pneumatic device 12.

The device according to the invention is stituted by:

A first fluid-tight, slightly elastic metal diaphragm 13 fixed between the storage chamber 2 and the cylindrical ring 5 bounding the intermediate chamber 4, the sealing being obtained by toroidal joints 14 and 15;

A striker member 16, also metal, soldered or welded on to the diaphragm 13 on the side facing the intermediate chamber 4;

A second fluid-tight metal diaphragm 17 fixed between the cylindrical ring 5 bounding the intermediate chamber 4 and the second cylindrical ring 6, the sealing being obtained by a toroidal joint 18; and

An approximately spherical metal dome 19 supporting the second diaphragm 17, its convex side facing the intermediate chamber 4. i

The dome 19 illustrated in FIGURE 2 is made up of two series of metal sectors, the first, triangular sectors 20 constituting the top portion of the dome 19 and the second, trapezoidal sectors 21 constituting an annular side wall portion. While all the triangular sectors 20 abut along their adjacent edges, the trapezoidal sectors 21, which are held at their bases, allow for a play of a few tenths of a millimeter towards the top. This is to allow for the shattering of the metal dome 19 in the course of the operation of the said device.

To keep the domed sectors in stable equilibrium when a uniform pressure is applied over the convex surface of the dome 19, each trapezoidal sector 21 is provided on its short base with a head 22 serving as a seating for the triangular sectors 20, and, on its long base, with a flattened edge 23 enabling it to be easily inserted into an annular slot 24 provided for this purpose in the cylindrical crown 6.

The assembled dome of triangular sectors 20 are supported on the beads 22 and are pressed against each other in the center of the crown of trapezoidal sectors 21 by essentially conthe normal pressure which is exerted on the dome assembly. This pressure, which is exerted by the inwardly curved membrane .17 supported on the said dome 19, contributes also to maintaining the edges 23 of the trapezoidal section 21 in the slot 24. The dome 19 may be assembled and mounted by first inverting the ring 6 and the diaphragm 17 in such a manner that the diaphragm 17 is convex, but is directed toward the base. The sectors 20 are then assembled in the center of this membrane and the sectors 21 are mounted between the sectors 20 and the slot 24. The assembly is finally inverted and mounted in place as shown in FIGURE 1.

It is clear that the thickness of the metal sectors 20 and 21 must be a function of the pressure the dome 19 will have to support.

The fluid-tight enclosure 1 provided with the device described above is positioned in the reactor in such a way that the release chamber 3 is located in the actual core of the reactor whereas the storage chamber 2 is placed directly above it. The neutron-absorbing fluid is enclosed in the storage chamber 2 under a pressure much higher than that present in the release chamber 3. To give a clearer picture, an experiment was made with a. pressure of 80 atmospheres in the storage chamber and a pressure of 1 to 2 atmospheres in the release chamber. The pressure in the intermediate chamber 4 is made equal to the pressure in the storage chamber 2. Hence the diaphragm 13 is not subjected to any stress. The dome 19, however, is supporting considerable pressure, whereas the diaphragm 17 resting on the said dome and the function of which is solely to provide a seal for the intermediate chamber 4, operates under good conditions.

The device operates in the following manner: an abrupt fall in pressure is effected in the intermediate chamber 4 so as to bring the pressure in it down .to the pressure in the release chamber 3. The diaphragm 13, which is subject to a strong pressure, is deformed at this point. The striker member 16 ruptures the top of the dome 19. The diaphragms 13 and 17 burst when the triangular sectors 20 are forced back into the release chamber .as shown in FIGURE 3a.

The striker member 16 pressing on the trapezoidal sectors 21 forces them back-in their turn (FIGURE 3b) and is then itself carried into the release chamber 3 by the action of the fluid under pressure (FIGURE 30).

In another embod-imentmentioned as an example the metal dome 19 and its fluid-tight diaphragm 17 are replaced by a glass dome.

It goes without saying that the present invention is not limited to the embodiment described above and that the scope of the present specification extends to any device including its application.

I claim:

1. A safety device for providing rapid communication between a high-pressure reservoir having an outlet passageway and a low-pressure reservoir having an inlet passageway, comprising:

(a) means defining an intermediate chamber disposed between said reservoirs, said intermediate chamber i being open at either end thereof for communication at one end with the outlet passageway of said highpressure reservoir and at the other end with the inlet passageway of said low-pressure reservoir;

(b) a first fluid tight diaphragm disposed in sealing relation across said other end to seal off communication between said intermediate chamber and said lowpressure reservoir; said first diaphragm being con- \fiXed in the direction facing said intermediate chamer;

(c) a rigid but frangible dish-shaped supporting member supported at its periphery in said inlet passageway contiguous to the concave surface of said first diaphragm and in underlying relation thereto, said supporting member being convex in the direction of said intermediate chamber and comprising an annular side wall portion made up of a plurality of trapezoidal sectors and a center portion made up of a plurality of triangular sectors, said trapezoidal sectors having a bead at the inner edge thereof, the outer side edge of said triangular sectors seating on said beads forming a self-supporting dome, said supporting member being adapted to fragment under the act-ipn of a member striking the convex surface there- 0 (d) a second fluid-tight diaphragm disposed in sealing relation across said one end of said intermediate chamber to seal off communication between said intermediate chamber and said high-pressure reservoir; and

(e) a striker member provided within said intermediate chamber and secured to the undersurface of said second diaphragm, said striker member being adapted for movement with said second diaphragm under the influence of a predetermined drop in pressure in said intermediate chamber to strike and fragment said dish-shaped member and permit said first diaphragm to rupture.

2. A device as claimed in claim 1, wherein the long bases of the trapezoidal sectors are in contact and a slight amount of play is provided between the short bases of the said trapezoidal sectors.

3. A device as claimed in claim 1, wherein the sides of the adjacent triangular sectors are in close contact with one another.

4. A device as claimed in claim 1, wherein said dishshaped member is in the form of a portion of a sphere and is made of glass.

References Cited by the Examiner UNITED STATES PATENTS 2,387,353 10/45 Raymond 220-89 2,586,858 2/52 Parsons 22089 2,788,794 4/57 Holinger 22089 2,889,071 6/59 COiTman 220-89 3,092,286 6/63 Duff 22047 LOUIS G. MANCENE, Primary Examiner.

THERON E. CONDON, Examiner. 

1. A SAFETY DEVICE FOR PROVIDING RAPID COMMUNICATION BETWEEN A HIGH-PRESSURE RESERVOIR HAVING AN OUTLET PASSAGEWAY AND A LOW-PRESSURE RESERVOIR HAVING AN INLET PASSAGEWAY, COMPRISING: (A) MEANS DEFINING AN INTERMEDIATE CHAMBER DISPOSED BETWEEN SAID RESERVOIRS, SAID INTERMEDIATE CHAMBER BEING OPEN AT EITHER END THEREOF FOR COMMUNICATION AT ONE END WITH THE OUTLET PASSAGEWAY OF SAID HIGHPRESSURE RESERVOIR AND AT THE OTHER END WITH THE INLET PASSAGEWAY OF SAID LOW-PRESSURE RESERVOIR; (B) A FIRST FLUID TIGHT DIAPHRAGM DISPOSED IN SEALING RELATION ACROSS SAID OTHER END TO SEAL OFF COMMUNICATION BETWEEN SAID INTERMEDIATE CHAMBER AND SAID LOWPRESSURE RESERVOIR; SAID FIRST DIAPHRAGM BEING CONVEXED IN THE DIRECTION FACING SAID INTERMEDIATE CHAMBER; (C) A RIGID BUT FRANGIBLE DISH-SHAPED SUPPORTING MEMBER SUPPORTED AT ITS PERIPHERY IN SAID INLET PASSAGEWAY CONTIGUOUS TO THE CONCAVE SURFACE OF SAID FIRST DIAPHRAGM AND IN UNDERLYING RELATION THERETO, SAID SUPPORTING MEMBER BEING CONVEX IN THE DIRECTION OF SAID INTERMEDIATE CHAMBER AND COMPRISING AN ANNULAR SIDE WALL PORTION MADE UP OF A PLURALITY OF TRAPEZOIDAL SECTORS AND A CENTER PORTION MADE UP OF A PLURALITY OF TRIANGULAR SECTORS, SAID TRAPEZOIDAL SECTORS HAVING A BEAD AT THE INNER EDGE THEROF, THE OUTER SIDE EDGE OF SAID TRIANGULAR SECTORS SEATING ON SAID BEADS FORMING A SELF-SUPPORTING DOME, SAID SUPPORTING MEMBER BEING ADAPTED TO FRAGMENT UNDER THE ACTION OF A MEMBER STRIKING THE CONVEX SURFACE THEREOF; (D) A SECOND FLUID-TIGHT DIAPHRAGM DISPOSED IN SEALING RELATION ACROSS SAID ONE END OF SAID INTERMEDIATE CHAMBER TO SEAL OFF COMMUNICATION BETWEEN SAID INTERMEDIATE CHAMBER AND SAID HIGH-PRESSURE RESERVOIR; AND (E) A STRIKER MEMBER PROVIDED WITHIN SAID INTERMEDIATE CHAMBER AND SECURED TO THE UNDERSURFACE OF SAID SECOND DIAPHRAGM, SAID STRIKER MEMBER BEING ADAPTED FOR MOVEMENT WITH SAID SECOND DIAPHRAGM UNDER THE INFLUENCE OF A PREDETERMINED DROP IN PRESSURE IN SAID INTERMEDIATE CHAMBER TO STRIKE AND FRAGMENT SAID DISH-SHAPED MEMBER AND PERMIT SAID FIRST DIAPHRAGM TO RUPTURE. 